The invention relates generally to implants and, in particular, a single-stage dental implant that promotes healing of the gingiva and osseointegration simultaneously.
It is becoming more common to replace a missing tooth with a prosthetic tooth that is placed upon and attached to a dental implant. The dental implant serves as the artificial root in that it integrates with the jawbone. The prosthetic tooth preferably has a size and a color that mimics the missing natural tooth. Consequently, the patient has an aesthetically pleasing and structurally sound artificial tooth.
Current methods by which the prosthetic tooth and implant are completely integrated into the patient""s mouth require six to ten months, and sometimes longer, because two distinct, time-consuming steps are involved. First, the implant is inserted into the jawbone and covered by suturing the overlying gingival tissue. Covering the implant with the overlying gingiva is needed to minimize the likelihood of infection around the implant. Covering the implant also helps to guard against any disturbances of the implant that may slow its rate of osseointegration. The implant then osseointegrates with the jawbone for a period, usually in the range of three to six months.
After osseointegration is complete, the second step is encountered in which the gingiva is again cut open and a healing abutment is placed onto the implant. The overlying gingiva is sutured to allow it to properly heal around the healing abutment. Thus, when the prosthetic tooth is eventually placed upon the implant, the gingiva nicely conforms around the prosthetic tooth. However, it typically takes four to eight weeks before the gingiva is healed and the prosthetic tooth can be placed on the implant to complete the overall process. These implants can be referred to as xe2x80x9csubgingival implants.xe2x80x9d
Single-stage implants or xe2x80x9ctransgingival implantsxe2x80x9d simultaneously promote osseointegration and the healing of the gingiva. This is accomplished by providing an implant that has a portion that integrates with the jawbone and a portion that extends through the overlying gingiva so that the gingiva properly heals therearound. Thus, the four to eight week gingival healing process occurs during the three to six month period of osseointegration. Consequently, the patient is fitted with a prosthesis in a shorter period of time. And, the gingiva is lacerated and sutured one less time compared with two-stage systems which reduces the trauma to that region, the discomfort experienced by the patient, and the overall cost because the number of dental procedures is minimized.
It is sometimes desirable to convert a subgingival implant to the configuration of a transgingival style or vice versa. For example, if one style is best suited for installation in a first site in a patient""s jawbone, but another style is best suited for installation in another site, the restoring dentist seeking to fashion a bridge supported on implants installed in both sites might prefer to convert one style to the other in order to make the bridge using common components. Similarly, if a restoring dentist has on hand implants of one style and components for a new improved style become available, for reasons of economy it might be desirable to convert the available implants to the new styles so they can be used with the new components. However, known transition components introduce gaps between the components and present alignment problems for the restoration components.
Furthermore, during the preparation of dental restorations supported on artificial roots implanted in living jawbone, it is frequently useful to provide a temporary cover for a post or abutment (that eventually holds the artificial dentition) supported on a transgingival implant. It is also desirable to prevent the gingival tissue from collapsing around the transgingival implant or to maintain an opening in the tissue at least until temporary dentition is made. This invention also relates to a temporary cap useful to cover such abutments and posts for a transgingival implant.
The single-stage dental implant is typically installed through a ridge in the jawbone that is covered by gingival tissue. The dental implant provides an artificial root on which a prosthetic tooth is mounted to replace a missing tooth which formerly emerged from the jawbone. The single-stage implant comprises an anchoring portion for extending into and integrating with the jawbone and an integral gingival section that extends beyond the ridge of the jawbone. Because the gingival section is integral with the anchoring portion, there is no seam in which bacteria may collect to cause infections.
The implant has various embodiments with various internal structures which allow the implant to be driven into the bone tissue in the patient""s mouth. These internal structures typically engage a carrier that is delivered with the implant. Thus, the clinician uses tools that engage the carrier to drive the implant to the appropriate depth. After insertion, the clinician removes the carrier from the implant and a cover screw is placed thereover. The implant also has structural features enhancing its ability to support the artificial dentition on the post.
The inventive single-stage system also includes conversion components that allow a subgingival implant to have the same contour and structure as a transgingival implant. To convert a subgingival implant, a tubular member having an outer counter the same as the gingival head section of the transgingival implant is non-rotationally attached to the hexagonal fitting on the upper end of the subgingival implant. The fastener holding the tubular member on the implant extends above the tubular component and usually contains a non-rotational fitting (e.g. a hexagon). To convert the transgingival implant, a single transition component is threaded into the bore of the transgingival implant. The upper part of the transition component has the same contour as the portion of the fastener (used with the tubular member) extending above the tubular member. Thus, these conversion components provide a precise configuration that is present on both a converted transgingival implant and a converted subgingival implant which allows both to use the same restoration components.
The inventive single-stage implant system further contemplates novel components to mate with the posts of the implants. The posts and abutments (hereinafter xe2x80x9cpostsxe2x80x9d for convenience) on which artificial teeth are mounted generally extend supragingivally from a base at or beneath the gum surface to an end that may be narrower than the base. One inventive cap is hollow and open at least at its lower end so as to envelop the post in a generally telescopic manner when placed over the post. The end of the cap facing the base of the post is fitted with a rim enclosing an annular hollow space so as to snap over the periphery of the base when the cap encloses the post. When so fitted over the post, the cap covers the post and prevents the gum tissue from collapsing around the base of the post and top of the implant. It may also maintain an opening through the gum tissue for use by the restored tooth that is eventually mounted on the post. If it is desired for the cap to function as a temporary tooth, a suitable temporary cement can be used to fill the space between the cap and the post, in which event the hole in the top of the cap will serve as a vent for excess cement.
In another embodiment of the invention, the cap is open at its top and has perforations through its sides. When this embodiment is fitted over the post and covered with a tooth-shaped shell filled with a suitable dental plastic material that can be forced through the perforations into contact with the post and allowed to harden in a short time, a temporary tooth in the shape of the shell can be fashioned at chairside in the mouth of a patient, or on a model of the patient""s case out of the patient""s mouth. When the plastic material hardens, the shell can be removed, and this tooth can be cemented to the post to function as a temporary tooth which is cosmetically similar to adjacent teeth.
The above summary of the present invention is not intended to represent each embodiment, or every aspect, of the present invention. This is the purpose of the figures and the detailed description which follow.